Last time I checked there are plenty of other stars playing the same minutes and not getting hurt. The only difference is many teams don't rely on their stars to be their main defenders. It's more personnel than minutes.
This is a big difference if you ask me.
I don't see Zach Lavine doing this on both ends
Your examples were IT, Irving, Kemba, Smart, and Brown. Really only Brown is asked to carry the load on both ends.
IT -- Small guy who played as hard as he could, constantly going into the paint and absorbing contact.
Irving -- There were plenty of stories prior to his being traded that he was hurt, and would need surgery sometime. The negative spin during that period is that he planned to have it at the worst time for the Cavs, but then he played for the C's and ultimately needed it at a time that cost him the end of the season and the playoffs anyway.
Kemba -- He averaged 2800 minutes a season his four years prior to arriving in Boston, not including playoff minutes. For perspective, he's at 2600 minutes since he's come to Boston, including 600 playoff minutes (a total of 84 games), so it's pretty likely the wear on Kemba happened before he came.
Smart -- All you have to do is watch him play to know that it's a matter of when, not if, he's going to get hurt.
Brown -- So far in his career, he seems like a guy who's going to miss 8-12 games a year, with 1-2 minor injuries a year. He's not a walking injury magnet, but he seems a bit more prone to soft tissue injuries. That said, he's likely not overworked in terms of minutes, and he's literally the only player you mentioned that carries the load at both ends of the court (and really this is the first season he's truly carried it on offense).